Imagine you're a shop assistant and I'm a customer. I'm talking on my phone and barely acknowledge you. Do you refuse to serve me? That's nice, you're still serving me. What if I'm using bad language? It seems you've heard it all before and you carry on. What about if I have no top on? You're still serving? That's very tolerant of you. What if I'm a woman? (I said this was imaginary.) You're not so sure now, are you? What if I'm not actually topless but I am breastfeeding?

And so it goes on. What complicated etiquette we have in today's society. Maybe I'm falling for the trap of imagining some golden age in the past but I am pretty sure what counted as good and bad manners used to be much more clear cut. Nowadays we have got used to the idea that we can do what we want within the law and, if someone doesn't like it, that's their problem.

Long gone are the days when every man expected to wear a tie at a restaurant or the theatre and every woman only showed the skin between her neck and her knees to people on the beach. Indeed it comes as quite a surprise to some people when they are forbidden to enter somewhere like the Royal enclosure at Ascot because they're a man in shorts or a woman without a hat.

It's a conundrum for the retailer. I've experienced many examples of bad manners from customers, people who don't say 'Thank you', others who let their children run wild, some who think they have the right to push in at the front of a queue. Do I show them the door? It's my shop so I can, within the law, serve or refuse to serve who I want. In practice, as long as they're paying for the goods, I'll put up with bad manners and only intervene if I think my stock's in danger or other customers are being driven out. Business should be about selling, not judging.

We all draw the line somewhere. What is the point at which bad manners becomes unacceptable rudeness? Very few people disagreed that the customer's use of her mobile at the checkout was poor behaviour but Sainsbury's said their assistant should still have served her. Tesco insist you wear a top if you want to shop with them. Apparently this is because they're worried about men with no tops dripping sweat on the stock but most of us would agree with the ban simply because we don't want to see hairy beer bellies while we're choosing our Sunday roast.

When a swimming pool in Cambridge banned a woman from breastfeeding last month, they tied themselves up in all kinds of knots. The woman was banned because of the rule that said no food or drink in the pool area! I myself banned food and drink in our shop but it never occurred to me to worry that a breastfeeding mum would accidentally squirt milk all over the stock. In any case, the Equality Act 2010 clearly states that it is unlawful to discriminate against someone breastfeeding in public. Ironically the woman posted a complaint on the pool's Facebook page. That's the same Facebook whose ban on photos of female nipples extends to ones being used to breastfeed. (They also censored an elbow that looked like a naked breast but that's another story- Google it if you don't believe me.)

Our very own Naked Rambler is a case in point where different situations and different people produce reactions ranging from bemused tolerance to arrest.

I'd rather live in a society which doesn't have unnecessary rules but I also believe society functions a lot better if we respect each other's sensibilities. (I think we used to call this growing up.) With this in mind, we can all set an example of politeness. Let's start with us retailers. If we want our customers to be polite, how about we make sure we and our staff stop chatting to each other or filling shelves when someone needs to be served? Let's seem like we are pleased to see the customer instead of acting bored or indifferent. Let's make sure we say 'please' and 'thank you' and stop chanting 'have a nice day' like robots. You never know, it might rub off on the lady with the mobile phone.